Applying Digital Twins to the Built Environment

A DIGITAL TWIN IS A CONNECTED, VIRTUAL REPLICA OF A PHYSICAL PRODUCT, ASSET, OR SYSTEM.

Digital twins turn the physical world into computable

objects. Computable objects provide a consistent

way for software to manage and represent entities

from the physical world. Digital twins can be used

to represent the past and present state of physical

objects, to predict the future state of physical

objects, and to simulate or test future processes

and changes to answer “what-if” questions.

Digital twins provide a way to combine a number of

techniques, such as streaming sensor data, analytics

and machine learning, and enabling knowledge graph

representations of the world, creating a developer-

friendly interface that bridges the digital and the

physical world. Although most of the techniques

already existed as stand-alone capabilities, digital

twins provide a common framework to bring them

together and more rapidly innovate.

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Improving Building Systems with a Digital Twin

One common application of a digital twin is modeling building systems. The twin uses information technology and operational technology, such as construction data and floor plans for the building, real-time sensor data from the building management system, data from HVAC systems, lighting, fire, security, and other environmental sensors, as well as data about the assets of the building and the people who use it, such as tenants, occupants, building staff, visitors, and other roles.

AFTER CONSTRUCTION

A building twin can predict: • Security incidents • Parts replacement schedules • System inefficiencies • Process integration impacts

BEFORE/DURING CONSTRUCTION

A building twin can identify & improve:• System interactions and integrations • Installation obstacles • Selection of providers • Cost and maintenance predictions • Construction risks

BUILDING A DIGITAL TWIN

All buildings have a lifecycle. It starts with the spark of an idea by a developer or other visionary about how to transform an existing building or to create something new. The lifecycle starts there and brings in the architects for the conceptual and engineering design phase and then moves into construction, commissioning, and then hopefully, a long, many-year stretch of operations and minor remodels to the building, until finally someone else comes along with a new spark of an idea and embarks on a major remodel or demolition of an existing building and starts the cycle over.

It is clear that having a digital twin - and the same digital twin - for all steps of the building lifecycle unlocks some powerful capabilities. Historically, there have been digital representations of a building, but typically, each phase of the building lifecycle ignored the digital representation from the previous phase so the data from the design phase was not used in the commissioning phase, and the commissioning data was not kept up-to-date in the operations phase. This meant that none of the digital representations of the building were ever truly complete or up-to-date and hence were never as powerful as an ideal digital twin could be.

Preferably, the digital twin is born first, before its physical counterpart. Long before construction begins, the architect creates the first version, and unlike the paper drawings of years past, the digital design can immediately become a living thing, standing in for the physical building in simulations. As the drawings and plans change, the digital twin in turn updates and recomputes itself. It can evaluate physical characteristics innate to the building itself, such as modeling airflow or energy usage, or it can evaluate the building in a larger environment, such as predicting the effect of the building on the traffic flow of the neighborhood. The digital twin may go through thousands of changes and millions of simulations before it is eventually used to guide the construction of its physical sibling.

In other cases, especially for existing buildings, the digital twin is born well after the physical version was created and placed into use. In this ordering, the first version of the digital twin stands as a very coarse approximation of the physical twin, and over time, as more data is measured or acquired and additional real-time sensors are integrated, the digital and physical versions become more alike in detail and fidelity.

Digital twins differ from Building Information Modeling (BIM) in that BIM is a process and digital twins are real-time virtual representations. BIM involves the generation and management of digital reproductions of physical and functional characteristics of places, whereas digital twins can serve as repositories of BIM data as well as a much broader array of building automation systems and sensor networks.

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APPLICATIONS FOR DIGITAL TWINS IN THE BUILT ENVIRONMENT

PredictionThe digital twin brings together all of the data necessary for predictive algorithms and artificial intelligence systems, from fault predictions on equipment to building utilization and optimization.

OperationsA digital twin of a building gives building managers and occupants a real-time view of the integrated systems of the building. This is a powerful construct that can be used for everything from top-line dashboards of building health to specific applications like asset and people tracking, hot desking, integration with transit and parking, and building operations based on conditions rather than fixed schedules.

Cost ReductionDigital twins help buildings operate more efficiently by helping predict and avoid unexpected costs, identify system inefficiencies, and better estimate when replacement parts are needed.

Risk MitigationRunning simulations on a digital twin reduces risks and helps system engineers make better business cases for changes to the system. Experimenting on the digital twin also can help mitigate equipment downtime.

Understanding System InteractionsDigital twins from multiple systems and objects can be combined to better understand how they will interact with each other. This is particularly helpful when systems and products come from different suppliers.

SecurityThe digital twin provides a real-time view of the building and its occupants while incorporating historic trend data. The digital twin can be used to highlight “abnormal” actions or events that could portend security issues.

The data collected for digital twins can come from a variety of sources. A true digital twin must be a “system of systems” integration:

• Embedded sensors: Used to create digital twins of individual equipment (e.g., an HVAC unit) or a larger system. Embedded sensors transmit operational data from equipment to operators who monitor the system and control it remotely. Equipment categorized as “smart” would allow for this.

• Wireless sensor networks: Installed in buildings to collect data on temperature, humidity, lighting, occupancy, and other factors. Wireless sensors have the advantages of easier system expansion, flexibility to relocate sensors as space needs change, and more seamless installation.

• Digitized building lifecycle data and systems: BIM data, connected and smart HVAC systems, digitized pneumatic thermostats, smart plugs, and smart elevator controls are all opportunities to channel data and build a digital twin.

• Integration with other cloud services and data providers: Data may be integrated into the digital twin from outside sources, such as weather data or from 3rd party “cloud to cloud” integrations. In cases where systems do not communicate directly with the local sensor network but instead connect to a 3rd party vendor’s cloud, the building must pull data from that vendor’s cloud.

Data Collection for Digital Twins

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1 reference IDC: Apr 2018 - IDC PlanScape - Doc # US43134418 IDC PlanScape: Digital Twins for Products, Assets, and Ecosystems

THE IMPACT OF DIGITAL TWINS

IDC research outlines a Digital Twin Maturity Model that begins with Digital Visualization and moves through Digital Development, Digital Enterprise, Digital Ecosystem, and finally Digital Twin Orchestration1. Digital twin technologies can have a positive impact on building management and operations across the entire value chain, moving from ideation and visualization of processes to service and management at a greater and greater scale. A mature digital twin allows for decision support and real-time visibility of products, assets, facilities, and manufacturing.

CHANGE MANAGEMENT

The digital twin is only as good as its input data. Enterprises have struggled to find value in their BIM practices because the BIM is rarely kept up-to-date. A digital twin of the building will also need to be kept up-to-date, but it is possible to use the digital twin of the building to help make the tools to keep the digital twin updated.

TECH OVERKILL

Digital twins aren’t always called for and can unnecessarily increase complexity.

CYBERSECURITY

Cyber intruders could potentially use a digital twin to gain access to confidential building information.

CONCERNS ABOUT DIGITAL TWINS

1

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LACK OF DATA STANDARDS

Standards would help companies make smart technology development investments.

Johnson Controls is a founding member of the Brick schema consortium that is working to standardize a unified approach to building representation.

Visit www.brickschema.org for more information.

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Case Study: Johnson Controls Digital Vault

THE JOHNSON CONTROLS DIGITAL VAULT ENABLES AND ENHANCES THE DEVELOPMENT OF A BUILDING DIGITAL TWIN. THIS ALLOWS FOR INCREASED PRODUCTIVITY, IMPROVED OCCUPANT COMFORT AND SAFETY, AND OPTIMIZED ENERGY EFFICIENCY.

For AssetsThe Digital Vault gateway collects real-time sensor data from Johnson Controls and non-Johnson Controls equipment and stores it in the Digital Vault. The metadata and configuration of the device is also stored. The Digital Vault recognizes the device type and automatically suggests and creates appropriate analytics and predictive models for the device. The Digital Vault provides a secure way to send commands and updates back to the device, closing the loop from model to prediction to control.

For PlacesBIM models, floor plans, and locations collected from devices /beacons can be ingested into the Digital Vault to reflect the most updated space configuration. Combining this data with the asset digital twins can provide the latest asset location and information.

For PeopleData obtained from enterprise people systems, office productivity software, access control systems, etc., can also be captured in the Digital Vault to create digital twins of the people in the space.

Data Ingestion

BUILD ING INFORMATION

MODEL

BIM

BUSINESS PROCESSES

SENSORSDES IGN PL ANS

BU ILD ING AUTOMATION

SYSTEM

SMART EQU IPMENT

Digital Vault

Digital Twin

CONVERGED & CONNECTEDSECURITY

FAULT DETECT ION & D IAGNOSTICS

R ISK S IMUL AT IONS

COST & MAINTENANCEPREDICTIONS

SYSTEM INTEGR ATIONS ANALYS IS

2 reference IDC: Cost Analysis of Inadequate Interoperability in the U.S. Capital Facilities Industry, National Institute of Standards and Technology, retrieved 4-19-2018 from https://nvlpubs.nist.gov/nistpubs/gcr/2004/NIST.GCR.04-867.pdf

ApplicationsDigital Vault provides additional context to make the digital twin more effective. It models not only devices but the entire built environment and enterprise around the device, so the digital twin can make informed decisions and respond to user requests. For example, the digital twin for a VAV box knows how to find the digital twin for the air handler that feeds it, so the analytics on the VAV box can automatically run algorithms using current and historic data for the AHU. Another example—a digital twin for the parking ramp knows how to communicate with the digital twin for the security system. So when an employee’s car is detected in the parking structure, the security cameras in the building expect the employee, who can then seamlessly enter the building from facial recognition alone.

Data ModelOne of the biggest challenges facing the global building industry today is the lack of a common data model for the applications and systems that exist within buildings. This prevents interoperability and limits scalability, issues that cost the industry an estimated $15 billion annually2. Brick is an open-source development effort designed to address that challenge by creating a uniform schema for representing metadata in buildings. Brick is flexible and expressive, enabling the next generation of building environments. Johnson Controls is a founding corporate sponsor of the Brick consortium, a group that will drive the development and adoption of Brick.

Visit www.brickschema.org for more information.

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